Semiconductor components, in particular diaphragm sensors, and methods for manufacturing diaphragm sensors on the basis of a semiconductor substrate, e.g., a silicon wafer, on which a flat, porous diaphragm region is situated as a support layer for sensor structures and which has a cavity under the diaphragm region for in particular thermal insulation of the diaphragm, are already known.
Most diaphragm sensors presently existing in the market are usually implemented as thin-film diaphragm sensors. For this purpose, layer systems are deposited on a substrate in thicknesses between a few tens of a nm and a few μm, and subsequently the substrate is removed in predefined regions to obtain unsupported diaphragm regions. Sensor structure elements can then be placed in the center of the diaphragm.
Another option for exposing the diaphragm is by use of surface micromechanics (SMM), in which a sacrificial layer is normally used, which is applied to the front of a carrier substrate before depositing the diaphragm. The sacrificial layer is later removed from the front of the sensor through “dissolution openings” in the diaphragm, whereby an unsupported structure is obtained. These surface micromechanical methods are relatively complicated due to the need for separate sacrificial layers.
German Patent Application No. DE 100 325 79.3 describes a method for manufacturing a semiconductor component and a semiconductor component manufactured by this method, in which a layer of porous semiconductor material is placed over a cavity for a diaphragm sensor in particular.
Using these measures, it is possible to considerably simplify the design of an SMM semiconductor component, because no sacrificial layer needs to be additionally applied, and the diaphragm itself or a substantial part thereof is produced from semiconductor material.
However, tests have shown that a porous diaphragm may be damaged as early as during manufacturing, and even under conventional conditions of use damage cannot always be reliably prevented.